"ps -e" without procfs(5)

Robert N. M. Watson rwatson at freebsd.org
Tue Oct 25 08:40:37 UTC 2011

On 25 Oct 2011, at 09:24, Kostik Belousov wrote:

> On Tue, Oct 25, 2011 at 12:13:10AM +0300, Mikolaj Golub wrote:
>> On Sun, 16 Oct 2011 20:10:05 +0300 Kostik Belousov wrote:
>> KB> In my opinion, the way to implement the feature is to (re)use
>> KB> linprocfs_doargv() and provide another kern.proc sysctl to retrieve the
>> KB> argv and env vectors. Then, ps(1) and procstat(1) can use it, as well as
>> KB> procfs and linprocfs inside the kernel.
>> Thanks! I am testing a patch (without auxv vector so far) and have some
>> questions.
>> Original ps -e returns environment only for user owned processes (the access is
>> restricted by the permissions of /proc/pid/mem file). My kern.proc.env sysctl
>> does not have such a restriction. I suppose I should add it? What function I
>> could use for this?
>> BTW, linprocfs allows to read other user's environment.
> linprocfs uses p_cansee() to check the permissions. There are sysctls
> security.bsd.see_other_{ug}ids that control the behaviour.
> I believe that the new sysctl shall use the same check.

To be honest, I'd be far more comfortable if the environment check used p_candebug(). Environmental variables sometimes contain passwords, etc, that shouldn't be visible to other users on the system. Even showing command lines is a bit dubious, but widely accepted, whereas seeing the contents of environmental variables is not widely known in user communities.


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